Ever heard of Ebola virus? It’s the deadly virus that is threatening to invade West Africa. As at last count, about 100 people in Guinea and Liberia are said to have died from the virus. The situation is so serious that even the World Health organization (WHO) has described it as one of the "most challenging incidents the world has ever seen”. If not properly handled there are concerns that the virus may well spread to other West African countries Nigeria inclusive.
Here are some facts you need to know about the virus:
• The Ebola virus causes Ebola virus disease (EVD; formerly known as Ebola haemorrhagic fever) in humans.
• EVD outbreaks have a case fatality rate of up to 90%.
• EVD outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests.
• The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission.
• Fruit bats are considered to be the natural host of the Ebola virus. Other bush game animals may also transmit the disease
• No specific treatment or vaccine is available for use in people or animals.
The Ebola virus causes Ebola virus disease (EVD) in humans, with a case fatality rate of up to 90%.
Ebola first appeared in 1976 in 2 simultaneous outbreaks, in Nzara, Sudan, and in Yambuku, Democratic Republic of Congo. The latter was in a village situated near the Ebola River, from which the disease takes its name.
Transmission
Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals. In Africa, infection has been documented through the handling of infected chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest.Ebola then spreads in the community through human-to-human transmission, with infection resulting from direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and indirect contact with environments contaminated with such fluids. Burial ceremonies in which mourners have direct contact with the body of the deceased person can also play a role in the transmission of Ebola. Men who have recovered from the disease can still transmit the virus through their semen for up to 7 weeks after recovery from illness.
Health-care workers have frequently been infected while treating patients with suspected or confirmed EVD. This has occurred through close contact with patients when infection control precautions are not strictly practiced.
Signs and symptoms
EVD is a severe acute viral illness often characterized by the sudden onset of fever, intense weakness, muscle pain, headache and sore throat. This is followed by vomiting, diarrhoea, rash, impaired kidney and liver function, and in some cases, both internal and external bleeding. Laboratory findings include low white blood cell and platelet counts and elevated liver enzymes.People are infectious as long as their blood and secretions contain the virus. Ebola virus was isolated from semen 61 days after onset of illness in a man who was infected in a laboratory.
The incubation period, that is, the time interval from infection with the virus to onset of symptoms, is 2 to 21 days.
Diagnosis
Other diseases that should be ruled out before a diagnosis of EVD can be made include: malaria, typhoid fever, shigellosis, cholera, leptospirosis, plague, rickettsiosis, relapsing fever, meningitis, hepatitis and other viral haemorrhagic fevers.Ebola virus infections can be diagnosed definitively in a laboratory through several types of tests:
• enzyme-linked immunosorbent assay (ELISA)
• antigen detection tests
• serum neutralization test
• reverse transcriptase polymerase chain reaction (RT-PCR) assay
• virus isolation by cell culture.
Samples from patients are an extreme biohazard risk; testing should be conducted under maximum biological containment conditions.
Prevention and treatment
No vaccine for EVD is available. Several vaccines are being tested, but none are available for clinical use.Severely ill patients require intensive supportive care. Patients are frequently dehydrated and require oral rehydration with solutions containing electrolytes or intravenous fluids.
No specific treatment is available. New drug therapies are being evaluated.
Natural host of Ebola virus
In Africa, fruit bats, are considered possible natural hosts for Ebola virus. As a result, the geographic distribution of Ebola viruses may overlap with the range of the fruit bats.
Ebola virus in animals
Although non-human primates have been a source of infection for humans, they are not thought to be the reservoir but rather an accidental host like human beings. Since 1994, Ebola outbreaks have been observed in chimpanzees and gorillas.Prevention
In the absence of effective treatment and a human vaccine, raising awareness of the risk factors for Ebola infection and the protective measures individuals can take is the only way to reduce human infection and death.In Africa, during EVD outbreaks, educational public health messages for risk reduction should focus on several factors:
• Reducing the risk of wildlife-to-human transmission from contact with infected fruit bats or monkeys/apes and the consumption of their raw meat. Animals should be handled with gloves and other appropriate protective clothing. Animal products (blood and meat) should be thoroughly cooked before consumption.
• Reducing the risk of human-to-human transmission in the community arising from direct or close contact with infected patients, particularly with their bodily fluids. Close physical contact with Ebola patients should be avoided. Gloves and appropriate personal protective equipment should be worn when taking care of ill patients at home. Regular hand washing is required after visiting patients in hospital, as well as after taking care of patients at home.
• Communities affected by Ebola should inform the population about the nature of the disease and about outbreak containment measures, including burial of the dead. People who have died from Ebola should be promptly and safely buried.
